Taxonomies can organize a set of concepts (or categories) by classifying well-defined underlying relationships between the different concepts. Examples of large taxonomies include the Open Directory Project (which may be found at www.dmoz.org) that contains categories which describe web page (i.e., URL) topics, and the category graph associated with Wikipedia documents (which may be found at www.wikipedia.org). The Open Directory Project (ODP) and Wikipedia have different graph topologies. The ODP's hierarchical taxonomy comprises a tree graph of around 600,000 nodes (i.e., categories), while Wikipedia's taxonomy comprises a directed graph containing approximately 900,000 nodes.
The description above is presented as a general overview of related art in this field and should not be construed as an admission that any of the information it contains constitutes prior art against the present patent application.